Effect evaluation of shale types on hydrocarbon potential using well logs and crossplot approach,Halewah oilfield,Sab'atayn Basin,Yemen

Log-analysts typically distinguish three types of shale distribution in clastic reservoirs,that is,laminated,dispersed and structural distribution,which tend to influence the effective porosity and permeability of reservoirs.The Alif Member is made up of sandstone interbedded with some shale,with shale dominating on top and at the bottom.In sedimentary formations,the gamma ray log normally reflects the shale content.The gamma ray log and neutron-density porosity crossplot is used to estimate a reservoir's shale volume(Vsh),according to which the Alif Member is divided into three zones.In addition,shale types are recognized by neutron-density porosity crossplot,and the correlation coefficients of gamma ray log-based Vsh and neutron-density porosity-based Vsh are suggested to be reliable.The Vsh and shale types of the three zones are compared against the reservoir's potential to yield hydrocarbons.The major oil intervals mainly concentrate in shaly sand and sandstone zones of dispersed and laminated shale types.The third zone,the lowermost interval,contains pure shale of laminated type and is considered out of reservoir standards in hydrocarbon production due to its excessive shale volume.Quantitative assessment of shale type distribution and Vsh by crossplot approach could not furnish correct information to evaluate massive shale intervals.

Contribution to the Characterization of Carbonate Rocks of the Nganzi Oil Exploration Block (Onshore of the DR Congo Coastal Basin)

The carbonate lithofacies of the Nganzi Exploratory Block located in the Lukula Territory in the Central Kongo Province were described in the field, sampled and subjected to microscopic, mineralogical, physico-chemical and petrophysical analyses. The aim is to increase the probability of discovery of deposits following the drilling of exploration wells in the most appropriate structures. These carbonates, limestones (white, greyish and greenish) and dolomites (massive and platelets) are presented in packstone, grainstone and wackestone textures. In addition to the essential minerals of these rocks, calcite and dolomite, we find quartz, plagioclase and kaolinite. With a porosity between 11% and 19% and a permeability of 138 to 155 mD, the Nganzi carbonates, which contain up to 23% oil, constitute good oil reservoirs. The characterization of the detrital facies and the acquisition of a seismic survey of the wells is essential to have a more detailed knowledge of the oil resources of the Nganzi Block.

Evaluation of aquifer hydraulic properties from resistivity and pumping test data in parts of Gwagwalada,Northcentral Nigeria

Population upsurge in Gwagwalada increased water demand in the area,thereby stressing water resources in the area.Aquifer properties in parts of Gwagwalada in North-Central Nigeria were therefore investigated using resistivity and hydrogeological approaches.Static water level measurements of hand dug wells were used to determine the groundwater flow direction for the area which coincides with the North East-South West joint direction.Constant rate pumping test was adopted for the research and 10 boreholes were pumped.The weathered/fractured basement range from 7.5 m to 56.7 m.The transmissivity values in the area ranged from 0.35 m^(2)/d to 3.63 m^(2)/d while the hydraulic conductivity range from 0.045 m/d to 0.18 m/d.The Vertical Electrical Soundings(VES)were carried out on the area.The geoelectric sections revealed four to five layers and the longitudinal conductance varied from 0.11Ω^(-1)to 0.37Ω^(-1).The results of the investigation characterized the groundwater potential in the study area into low and moderate while the aquifer protective capacity into weak and moderate zones.The efficacy of resistivity and pumping test data in quantifying aquifer properties has been established in this study.The findings of this study shed light on the properties of ground water and aquifer protective capacity in the area,hence assist in the effective future groundwater resources exploitation.

Granulometric and Mineralogical Characterization of the Sands of the Middle Course of the Kasai River (Territory of Ilebo, Province of Kasai/DR Congo)

The sand bars, in perpetual transformation, observable in the middle course of the Kasai river on the section between the city of Ilebo (pk605) to the confluence of the Loange river (pk525), pose enormous navigability problems. This may be dependent on hydrosedimentological characteristics of the Kasai River. This abundance of sand thus conditions the morphology of the middle course of the Kasai River in the section under our study. It therefore constitutes sedimentary navigation obstacles. The objective of this study is the granulometric and mineralogical characterization of the bar sands of the Kasai River in this study section. Particle size analyzes reveal these are moderately well classified to well classified unimodal sands (Classification coefficient between 1.29 to 1.742) largely presenting grain size symmetry and rarely fine asymmetry (Asymmetry coefficient—Skewness between −0.197 to 0.069) with mesorkurtic and rarely leptokurtic and platykurtic acuity (Angulosity coefficient—Kurtosis between 0.814 to 1.323). All these parameters evolve in sawtooth patterns from upstream to downstream. And then, an automated mineralogical analysis of the sands of the Kasaï River using a Qemscan FEG Quanta 650 made it possible to determine a very varied mineralogical procession with a sawtooth evolution. It is largely dominated by quartz (between 93.73% and 99.07%), followed by calcite (0.01% - 2.66%), iron oxides (0.01% - 1.88%), orthoclase (0.04% - 0.99%), plagioclase (0.01% - 0.75%) and Kaolinite (0.18% - 0.71%). Finally, this mineralogical procession is characterized by a group of minerals which do not reach the threshold of 0.55% such as: illite, apatite, ilmenite, muscovite, chlorite, biotite, montmorillonite, rutile, pyrophyllite, siderite, zircon and dolomite. The evolution of the mineralogical procession of the sands of the bars is not as clear as in the case of particle size parameters.

Exploratory and Descriptive Study of the Kimberlite Massif of Boya-02 at Eastern Kasai in the Democratic Republic of Congo

The Boya-02 kimberlite was identified at depth by geophysical survey work (a single-probe AM survey in 1997 and a gravity survey in 2006) that De Beers DRC Exploration carried out around anomaly 193/172/0019. This anomaly located approximately 50 km southwest of the town of Mbuji-Mayi in the Kasaï-Oriental Province in the DRC should therefore be the subject of detailed exploration with the aim of better identifying and describing this kimberlite. Thus, through exploratory work and cross-checking of geophysical and geological data, the discovery of this Massif was made by drilling on the aeromagnetic anomaly 193/172/X298. Based on drilling, sampling and laboratory petrographic analysis reports, the Boya-02 kimberlite was classified among highly diluted re-sedimented volcaniclastic kimberlites (KVR), rich in olivine and incidentally in quartz and poor in juvenile substances. This kimberlite represents a deposit of very low economic interest following extremely high dilution. The Boya-02 kimberlite was modeled using ground magnetism data. It is a complex anomaly comprising 2 components with variable amplitude appearing on a subtly magnetized linear detail. The modeled dimensions of two components of this anomaly are 0.32 Ha and 0.2 Ha at depths of 32 m & 14 m for the deposits to the West and the East respectively. Garnet data for the Boya-02 occurrence reports a maximum Pmin value of 49.7 kbar (207 garnets). These data demonstrate the high diamond potential which assumes a conductive cratonic geotherm of 40 mWm2.

Thermal conductivity modeling of water containing metal oxide nanoparticles

The nano particles have demonstrated great potential to improve the heat transfer characteristics of heat transfer fluids.Possible parameters responsible for this increase were studied. The heat transfer profile in the nanolayer region was combined with other parameters such as volume fraction, particle radius thermal conductivity of the fluid, particle and nanolayer, to formulate a thermal conductivity model. Results predicting the thermal conductivity of nanofluids using the model were compared with experimental results as well as studies by other researchers. The comparison of the results obtained for the Cu O/water and Ti O2/water nanofluids studied shows that the correlation proposed is in closest proximity in predicting the experimental results for the thermal conductivity of a nanofluid. Also, a parametric study was performed to understand how a number of factors affect the thermal conductivity of nanofluids using the developed correlation.

Contribution to the Improvement of the Petroleum Products Delivery Policy by the Implementation of a Computer System Based on the Dijkstra Method

The distribution and marketing of petroleum products are the sources of energy for the various activities of human society and household supply. We spent our time researching the competitive factors to reduce the time of distribution of petroleum products, by setting up a computer system based on Dijkstra’s algorithm our contribution will solve a real problem of delivery with direct targeting of gas stations. We set up a tool to help to map based on the method of operational research starting with the identification of delivery point, mapping and then applying the algorithm. Mainly the graph theory and the optimal path in a network by a short path using the method of Dijkstra for the design we used the UML language, the programming we used the JAVA language with very appreciable results to finish with a conclusion.

Geochemical Signature and Metalogeny of BIFs and Associated Iron Ore of Zatua Hills, Haut-Uele Province (DR Congo)

Zatua Hills are located in the northeastern part of the DR Congo in Haut Uélé Province, formerly known as Province Orientale. This part of DR Congo is identified by the high elevated zone, which has remained a witness to a stable zone not affected by the ancient erosion process. BIFs are most abundant and are dated to the Neoarchaean and Late Kibalian, hosted in the Upper Congo Granites Massifs of the DR. Congo. Zatua Hills consist of dolerite, phyllade, clay-rich sediment, poor itabirite, enriched BIFs, friable hematite, hard hematite, and mineralized and unmineralized breccias. Field study and geochemistry analysis by XRF, XRD, and ICP-MS are executed in order to know the geochemistry signature and paragenesis of Zatua Hills and the probably process could lead the BIFs to iron ore. The geochemistry analysis by XRF, XRD, and ICP-MS shows that Iron ore content has an iron rate between 57% and 69% with less deleterious elements such as Si, P, and Al. These deleterious elements are secondary and have silicium composition (probably quartz or chert, goethite, and Kaolinite), aluminum (probably gibbsite, variscite, cadwaladérite, goethite, and Kaolinite), phosphorous (probably variscite), and hydrated minerals, which are grown LOI in the samples. Hypogen and supergen processes are played in BIFs for iron ore conversion and, respectively, silica dissolution and leaching. Metamorphism was also impacted and marked by the Ti element (anatase) in samples, contributing to the crystallization of martite to hematite after magnetite oxidation.

Petrographic Characteristics and Metalogeny of Zatua Hills BIFs, Haut-Uele Province (DR Congo)

Zatua Hills are located at Haut Uélé Province of Democratic Republic of Congo (DRC), between northern Bafwasende and southern Paulis (Isiro) Squarred Degrees. Belonging to greenstone belt of Ngayu, that area is identified by the high elevated zone which is remained the witness of stable zone, not affected by the ancienst erosion process. Zatua Hills are in the superior Kibalian formation dated to Neoarchaen, hosted in Upper Congo Granites Massifs of DRC covering a large central zone of NE of DRC, and consisting to dolerite, phyllade, clay rich sediment, poor Banded Iron Formations (BIFs), enriched BIFs, friable hematite, hard hematite, mineralized and unmineralized brechias. Magnetite, martite and hematite are associated to some secondary minerals such as goethite, gibbsite, kaolinite, strengite, variscite and others clay minerals present in BIFs. Petrographic analysis made from the samples collected in situ showed, as well as BIFs and iron ore associated, that magnetite was much abundant oxide mineral which is oxided to martite before to stabilize to hematite during the deposition time. Having about hundred meters of thickness, the rich iron ore of this area content, in the majority less deleterious elements which, are harmful in metallurgic process of iron. These secondary minerals were precipitated at various degrees in the leached cavities of rocks between martite and hematite aggregates to botryoidal texture and, are rich to Al, and are mainly consisting to gibbsite and solid solution series of variscite-strengite (AlPO4·2H2O and FePO4·2H2O). Low degree of metamorphism played when magnetite was converted to martite, with the presence of variscite and anatase like witnesses of this event in which, martite was crystalized to hematite.

Extensive application of rate transient method in performance analysis for low permeability gas reservoirs

Rate transient method is a recently-developed performance analysis tool specially designed for low-permeability or tight gas reservoirs. This method, theoretically based on pressure transient analysis, integrates material balance principle and the concept of material balance pseudo-time proposed by Blansingame. With daily production data of gas well, it could be used to calculate OGIP, current formation pressure, permeability, skin factor, to identify complex geologic boundaries, to determine whether drainage boundary has been reached, to calculate drainage area and drainage radius for single well and to predict performance. It has been extensively employed in more than ten low-permeability gas fields. It proves that most problems in performance analysis for low permeability gas reservoirs could be solved by this method. Field practices show great economical benefits could be achieved by employing this method in gas field development.

Contribution to the Characterization Study of the Surface Indices of the Lotshi Block and Its Surroundings in the Coastal Basin of Congo

The Lotshi block with an area of 506 Km2, is located in the coastal basin in central Congo. It is between 12°31' and 12°53' east longitude and 05°33' and 05°44' south latitude. As part of this research, we carried out geological observations in the field, and sampled rocky materials in sites of petroleum interest in the Lotshi Block and surroundings in order to contribute to the understanding of the petroleum geology of this block, more particularly of its petroleum system. The samples brought back from the field were subjected to microscopic, mineralogical, (DRX), chemical (XRF) analyses and to the extraction of the hydrocarbon binder contained therein at the laboratories of ULG (Belgium), CRGM and OR in Kinshasa. The results obtained are summarized as follows: 1) Mineralogically: quartz, k-feldspar, plagioclase, calcite and dolomite are the dominant minerals in the samples analyzed;2) Lithologically: two lithofacies (quartz sandstone and carbonate sandstone);3) On the petroleum level: the sandstone rock of Lotshi and its surroundings are impregnated with hydrocarbons. It contains between 12% and 25% of hydrocarbon binder.

Source side seismic tomography(3STomo):A novelmethod to image the subsurface structure beneath seismically active region

We propose a novel seismic tomography method, Source Side Seismic Tomography （3STomo）, which is designed particularly to image the subsurface structure beneath seismically active regions. Unlike the teleseismic tomography, in which the data are relative traveltime residuals between closely spaced stations for each teleseismic event, 3STomo uses relative traveltime shifts between earthquakes within the study region for each distant station. Given the relatively evener distribution of global seismic stations, this method has unique advantages for imaging the structure beneath regions that have numerous earthquakes but lack of dense seismic stations, for example, some subduction zones and spreading ridges in the ocean. In addition, 3STomo has potentially better vertical resolution at shallow depths than the traditional teleseismic tomo- graphy. The effect of the inaccurate source parameters on its resolution can be minimized by using depth phases and the technique of joint source and structure inversion. Numerical experiments and application to Luzon Island, Philippines show that 3STomo can be a valuable tool to investigate the subsurface structure beneath some areas where the traditional method cannot be applied to, or at least it can be used as a complementary component of conventional teleseismic tomography to obtain better back-azimuth coverage and achieve higher resolution at shallow depths in the inversion.

稀有金属伟晶岩的地球化学和岩石成因:以刚果(金)Karagwe-Ankole成矿带Kivu地区Lemera锡矿床为例

本文报道刚果(金)Karagwe-Ankole成矿带Kivu地区Lemera花岗伟晶岩型锡矿床的岩石成因和地球化学研究结果。从露头采集7个花岗岩伟晶岩样品,并采用ICP-MS和XRF光谱法对其进行全岩岩石地球化学分析。花岗伟晶岩具有较高的Al_(2)O_(3)、较低的Fe_(2)O_(3)(T)和MgO含量(平均值分别为12.95%、0.96%和0.16%,质量分数),岩石铝饱和指数范围为1.33~2.05。一些重要稀有金属的丰度以及相关关键参数计算结果如下:Sn((1~138)×10^(-6))、Ta((0.20~0.60)×10^(-6))、Nb((1~8)×10^(-6))、Cs((1.20~3.20)×10^(-6))、Rb((3~223)×10^(-6))、Zr((7~201)×10^(-6));w(K)/w(Rb)(150~272);w(K)/w(Cs)(9.06~23.3),w(Nb)/w(Ta)(3.33~14)。结果表明,Lemera花岗伟晶岩形成于碰撞后期至后碰撞的构造环境中,由过铝质S型花岗岩岩浆结晶而成,岩浆经历了强烈的分离结晶作用。该岩体具有锡和锆的矿化。

Heavy Metal Levels and Potential Ecological Risks Assessed at an Agroecosystem Site in Tropical Region

The concentrations and distribution of thirteen metals and metalloids were investigated in soils, sediments, and two biological matrices (the fish Clarias gariepisnis and the earthworm Pontoscolex corethrurus) from the CECOMAF agroecosystem, in Kinshasa, Democratic Republic of the Congo, in order to assess the impact of anthropogenic activities. The results revealed high concentrations of heavy metals, such as Cu, Zn, As, Cd, Pb, and Hg all above values recommended by sediment quality guidelines and their probable effect levels on biota. According to the calculated Enrichment Factor, soil and sediments ranked from moderately to heavily polluted by Cu, Zn, Cd, Pb and Hg. The Contamination Degree and other ecological risk indices indicated very high contamination and very high ecological risks posed by Cd and Hg, respectively. The Geoaccumulation Index indicated that current metal concentrations in the agroecosystem originated from anthropogenic activities, while the Spearman correlation matrix values indicated that Hg could originate from different sources and pathways than the other metals. It was concluded that metals from unchecked anthropogenic activities have negatively impacted agricultural activities and fish production at the CECOMAF agroecosystem. Action to reduce the contamination level and the ecological risks by remediating and preventing metal pollution in the CECOMAF agroecosystem site is recommended.

A review on experimental techniques and their applications in the effects of mineral content on geomechanical properties of reservoir shale rock

Understanding the effects of mineral composition on geomechanical characteristics is critical in order to design and optimize the hydraulic fracturing necessary for shale gas reservoir production.Fundamental information is still missing in effects of mineral content and the experimental methodologies used.This paper provided an in-depth assessment of the various experimental methodologies and their applications in the relationship between the mineralogical and geomechanical features of the shale formation.The results revealed that more brittle minerals increase their strength,but chemical reaction that creats pores decrease their strength.High content of carbonate or quartz increases a rock's brittleness,while a high content of clay increases a rock's plasticity and decreases its brittleness.As phyllosilicate content increases,the uniaxial compressive strength decreases,and this could be because phyllosilicate minerals have a weakening effect on the mineral bond.Young's modulus often climb as clay minerals decline and as silica with carbonate concentration rises,however Poisson's ratio increases in relation to an increase in clay minerals,which also increases the ductility of the reservoir shale rock.However,compared to minerals and matrix,does not significantly impact the strength of shale rock.Besides,the benefits and drawbacks of using uniaxial and triaxial compression,ultrasonic testing,and nano-indentation techniques in unconventional reservoirs were described.The findings suggest that,because of the possibility for experimental testing repeatability for increased accuracy,ultrasonic testing is the most appropriate experimental approach in the scenes of assessing static and dynamic geomechanical properties of reservoir shale rock.We suggested that numerically-based simulation of experimental techniques used for shale geomechanical evaluations and numer-ical modeling of heterogeneous shale rock samples will be necessary in light of the limitations faced in the ap-plications of experimental techniques for shale geomechanical evaluation.